Logging
In plain terms
Recording events and messages from a running system.
Going deeper
Logs capture what software does, errors, requests, state changes, providing a trail for debugging, auditing, and monitoring. Structured, leveled logs make them searchable and useful at scale.
Under the hood
Structured (JSON) logs with levels and correlation IDs enable searching at scale; over-logging costs money and noise, under-logging blinds you.
Examples
log levels (DEBUG/INFO/ERROR), ELK stack, structured logging, correlation IDs.
Think of it like...
Like a ship's logbook noting every notable event, so you can reconstruct what happened when something goes wrong.